Production of acetylene



Patented Mar. 18, 1941 UNITED STATES PATENT OFFICE PRODUCTION OFACETYLENE Hans Klein, Hans Sachsse, and Wilhelm Hofeditz,

Mannheim, and Ferdinand Haubach, Lndwigshaten-on-the-Rhine, Germany,

Farbenindustrie assignors to Aktiengesellschaft,

Frankfort-on-the-Main, Germany NJ Drawing. Application January 27, 1938.Serial No. 187,164. In Germany February 2, 1937 4 Claims.

the oxygen, which may also be preheated if desired, and then conveyingthe mixture into the reaction space with such a speed of flow that theformation of a flame takes place only at some distance past the placewhere the gases meet the amounts of oxygen used, being such as arenecessary for the formation of a flame after mixing has been completed.

In another gas reaction, namely in the production of olefines fromsaturated hydrocarbons,

it has already been proposed to heat up the hydrocarbons and the oxygenseparately and when bringing the gases together to' take care that noformation of flame or local overheating takes place. Whereas for theformation of olefines the formation of flame is to be avoided, in thepreparation of acetylene from hydrocarbons the formation of flame isaimed at, but it has been found necessary to prevent the formation ofthe flame at the point of mixing while working with mixtures rich enoughin oxygen to enable the formation of a. flame.

It is surprising that by using appropriately high speeds of flow theformation of flame, in spite of the large amount of oxygen supplied, canbe retarded until a complete mixing of the hydrocarbons and oxygen hastaken place and that the flame is only formed at some distance from thepoint of mixing without any danger of striking back.

The necessary speed of flow of the gases depends on their temperatureand on the diameter of the tubular conduits used. Thus for examplemethane which has been heated to 750 C. and which is in a tube having adiameter of 1 centimeter must have a speed of at least 2 meters persecond in order to prevent the formation of flame at the point ofmixing. With an appropriate speed of flowit is possible to obtain at themixing point a gas mixture the temperature of which lies above thenormal ignition temperature. Even at these high temperatures, the timefrom the coming together of the gases to the ignition is sufllcient forthorough mixing of the gases provided the speed of flow is suflicientlyhigh.

In order to avoid premature ignition, it is espe- 5 cially advantageousto lead together the separately heated hydrocarbon and the cold orpreheated oxygen with a high and different speed of flow.

The following examples will further illustrate the nature of thisinvention but the invention is not restricted to these examples.

Example 1 A current of methane at a temperature of 750 C. is led at alinear speed of meters per second through a. tube having an internalwidth of 4 centimeters; into this current of methane there is ledthrough a tube of an internal width of about 0.9 centimeter a current ofoxygen heated to 750 C. at a speed of 100 meters per second and in suchan amount that the gas mixture contains 40 per cent of oxygen. Afterless than 0.01 second complete mixing has taken place. The mixture thenflows at a speed of meters per second into a wider reaction chamber inwhich a. flame forms. No ignition of the gases takes place at thepoint'of mixing, nor does the flame strike back to the point of mixing.30

For each part by volume of methane there are obtained about 2 parts byvolume of a gas mix ture containing from 8.5 to 9 per cent of acetylene.

Example 2 Propane is heated to 620 C. and caused to flow at a speed of 5meters per second into a reaction chamber; to the propane there issupplied oxygen at a temperature of 600 C. at a speed of 25 meters. persecond in such an amount 40 that the mixture contains 62 per cent ofoxygen. After complete mixing, the gas which now has a speed of flow of10 meters per second forms a flame and is converted into acetylene. Noignitlon of the gases at the point of mixing takes a place, nor does anystriking back ;take place. The amount of final gas is about five timesthat of the propane used and it contains from 9 to 10 per cent ofacetylene.

What we claim is:

1. A process for the production of acetylene by incomplete combustion ofa hydrocarbon which comprises heating the hydrocarbon, admixing it withoxygen, and conveying the mixture at a temperature at least as high asits 55 ignition temperature into the reaction space at such a speed offlow that the flame is formed at a distance from the point of Jointureof the gases where complete mixing of the hydrocarbon and oxygen hasoccurred, the amount of oxygen used being such as is necessary for theformation of the flame after mixture of the gases has been completed.

2. In the process of claim 1 the step of preheating the oxygen andmixing it with the hydrocarbon which has also been preheated. I

3. In the process of claim 1 the step of admixing the preheatedhydrocarbon and the oxygen at high and difierent speeds of flow.

4. In the process of claim 1 the step of mixing the two preheated gaseshaving, after mixing, a temperature which lies above the normal ignitiontemperature at such a speed of flow that no flame is formed until thegases are completely mixed.

HANS KLEIN. HANS SACHSSE. WILHELM HOFEDITZ. FERDINAND HAUBACH.

